None.
The present invention relates generally to the art of document processing equipment such as scanners, printers, facsimile machines and combination devices which use single sheet feeders to pick single sheets of media to be processed from a stack thereof. Such equipment includes sheet moving rollers, belts or wheels and, in particular, the sheet feeders with which the present invention is concerned employ both a pre-feed roller and a separation roller spaced downstream from the pre-feed roller. A stack stop is positioned to be moved into and out of the path of sheet movement between the rollers. Worn or otherwise damaged rollers in such equipment occasionally require replacement necessitating a service call and attendant expense. It is accordingly desirable to provide a modular single sheet feeder which can be easily assembled at the factory and which also has easily replaceable rollers which can be serviced by the user without the necessity to involve a skilled service technician.
The present invention therefore provides a sheet feeder comprising:
a) a tray having a support surface and spaced sides defining a sheet delivery path;
b) a roller support assembly pivotally mounted on said tray, said assembly including a frame having a sheet engaging roller and roller drive gears thereon, said roller support and drive assembly including:
1) a shaft extending transversely above said sheet delivery path and a biasing member for rotating said shaft relative to said tray;
2) at least one load arm fixedly attached to said shaft, said frame being pivotally affixed to said load arm, said shaft biasing said frame toward said support surface;
3) a cam coaxially rotatably mounted on said shaft, said cam including a cylindrical surface and an aperture in said surface;
4) a follower pivotally supported on said assembly for rotation about an axis parallel to said shaft, said follower having a finger engageable with said cam surface and said aperture and having a first cam surface engageable with said frame;
5) a swing arm rotatably mounted on said shaft, said swing arm engaging said follower to pivot said follower;
6) an input gear and a clutch gear mounted on said swing arm, said input gear being affixed to said cam and engaged with said clutch gear, said clutch gear being engageable with a roller drive gear on said frame as said swing arm rotates on said shaft in a forward sheet delivery direction, and said swing arm rotating on said shaft to disengage said clutch gear from said roller drive gear when input power is applied in a reverse direction and when a roller is over driven.
The present invention further provides a sheet feeder comprising:
a) a tray having a support surface and spaced sides defining a sheet delivery path; and
b) a roller support assembly which includes a frame having a pre-feed roller and a separation roller mounted thereon, said assembly being pivotally mounted on said tray, said assembly comprising:
1) a shaft extending transversely above said sheet delivery path and a biasing member for rotating said shaft to urge said rollers toward said support surface;
2) at least one load arm fixedly attached to said shaft for pivotally supporting said roller frame;
3) a cam rotatably mounted on said shaft, said cam including a cylindrical surface and an aperture in said surface;
4) a follower pivotally supported on said load arm for rotation about an axis parallel to said shaft, said follower having a finger engageable with said cam surface, said finger being moveable into said aperture during forward rotation of said cam in a sheet delivery direction, said follower having a first follower cam surface engageable with said frame for moving said frame and roller away from said support surface during reverse rotation of said cam, said follower having a second cam surface;
5) a swing arm rotatably mounted on said shaft, said swing arm engaging said follower during said reverse rotation to pivot said follower to remove said finger from said aperture; and
6) a stack stop pivotally mounted on said assembly and engageable by said second cam surface to move said stack stop in a path extending between said pre-feed roller and said separation roller out of a path of movement of a media sheet when said finger is in said aperture during said forward rotation.
The invention further provides a sheet feeder comprising:
a) a tray having a support surface and spaced sides defining a sheet delivery path; and
b) a roller support assembly mounted on said tray, said assembly including a rotary input gear mounted on support structure; and
c) an input gear retainer coaxially mounted on said support structure with said input gear, said retainer having a cylindrical surface which provides a motion limit surface for engagement by a pivotal motor output gear arm to prevent over engagement of teeth on said output gear and said input gear.